The overarching goal of this study is to advance our understanding of ethical issues that commonly emerge in interactions between HIV researchers and community-based organizations (CBOs) that serve populations at high risk for acquiring or living with HIV. By doing so, we will produce initial data essential for deriving principles which can be used to distinguish acceptable from unacceptable ways of structuring researcher/CBO relationships. Three groups of people of particular importance to HIV-related research - sex workers, Black men who have sex with men, and people who inject drugs - can be among the most difficult populations for researchers to recruit and retain in studies. Research in the U.S. with these populations has frequently involved collaboration and partnering with community based organizations (CBOs) such as AIDS service organizations, drug treatment programs, street outreach, and needle exchange programs. Despite being extremely common, these relationships between researchers and CBOs are largely unstudied, and yet have substantial practical and ethical implications. We argue that collaboration with research entails real ethical dilemmas and risks, as well as practical burdens for CBOs, just as it can do for research subjects. However, few if any of the current mechanisms for reviewing and monitoring the ethical conduct of research address or monitor researcher/CBO relationships, and few guidelines exist to assist researchers and CBOs considering such relationships. These risks can be extremely broad, and in our experience have included everything from damage to the trust relationships between a CBO and the community it serves when researchers they had publicly supported were seen as behaving 'disrespectfully' toward study subjects through to the loss of a needle exchange site due to increased foot traffic from a research project upsetting neighbors. While the vast majority of CBO/researcher interactions are positive for both parties, negative outcomes from collaborating or cooperating with HIV research mean CBOs can and do routinely make decisions to not collaborate with HIV research, an outcome which has serious ethical, social, and scientific implications. Regulation of the ethical conduct of research with human subjects is based on the application of ethical principles. Those principles were derived from empirical analysis of the commonalities shared by past cases of research misconduct. This project proposes to use two approaches to replicate this process, by empirically describing and categorizing common difficulties, risks, and burdens that arise in partnerships between HIV researchers and CBOs working with three key HIV risk/prevalence communities, and to use these data to develop a preliminary set of principles which can be used to guide future CBO/researcher collaborations.